Failed MMX attempt.

gistfile1.c

static uint32_t pixel_magnitude(uint32 pixel, uint32 color) {
    _m_empty();
    __m64 null_ = _m_from_int(0x00000000);
    __m64 pixel_ = _m_from_int(pixel);
    pixel_ = _mm_unpacklo_pi8(pixel_, null_);
    __m64 color_ = _m_from_int(color);
    color_ = _mm_unpacklo_pi8(color_, null_);
    pixel_ = _mm_sub_pi16(color_, pixel_);
    pixel_ = _mm_madd_pi16(pixel_, pixel_);
    color_ = _mm_srli_si64(pixel_, 32);
    pixel_ = _mm_add_pi32(color_, pixel_);
    int empty, out;
    _mm_set_pi32(empty, out);
    return out;
}